trionychina

from The Collaborative International Dictionary of English v.0.48

Trionychoidea \Tri*on`y*choi"de*a\, n. pl. [NL. See {Trionyx},
   and {-old}.] (Zool.)
   A division of chelonians which comprises Trionyx and allied
   genera; -- called also {Trionychoides}, and {Trionychina}.
   [1913 Webster]